Ingot mold



Patented M 3,1931

UNITED sTATEs PATENT. OFFICE EDWARD R. WILLIAMS, 0] LATROBE,PENNSYLVANIA, ASSIGNOR TO VULCAN MOLD AND IRON COMPANY, OF LA'IROBE,PENNSYLVfZNIA, A CORPORATION OF PENN- SYLVANIA meow MOLD 1T0.- Drawing.

Iron ingot molds made by the direct metal process or with iron as itcomes in the molten state from the blast furnace have a number ofdisadvantages. The temperature ofthe molten iron from the time it leavesthe blast furnace untilit is poured into the mold he'- comes lower whichreduces by precipitation the amount of carbon held in solution. Thisprecipitated carbon or kish promotes porosity in the mold casting,particularl at its top. The temperature of the molten lIOIl beingcomparatively low reduces its fluidity, and unless the mold wall isfairly thick, as

' four inches or more, the metal tends to coldheating and cooling inuse. Lar e graphite flakes render the metal relative y weak ascomparedwith metal having small graphite flakes.

By melting pig iron in a cupola or a similar re-melting' medium betterphysical properties are produced than by the direct metal process. Thehigh melting temperature we vailing in the cupola gives the metal betterfluidity than the direct metal from a blast furnace has and thereforegives the casting a smoother surface. The cupola method of producingcast iron affords a better control of the melting temperature than isobtainable by the direct metal method, owing to the ease of manipulatingthe coke ratio in a short eriod of time. Also the cupola method givesbetter control of the composition of the iron as to the percentage ofsilicon, phosphorus, carbon and manganese therein. Cupola metal asgenerally made has a serious disadvantage, particularly when cast asingot molds of large size. During the melting operation sulphur isabsorbed from the fuel to the extent of from .02% to 05%, which pro-Application filed June 22, 1929. Serial No. 373,058.

duces sulphur in the resultant casting of over .05% and sometimes ashighas 15%, depending on conditions. High sulphur content renders the ingotmolds red-short which, if the mold wall has insuflicient structuralstrength, allows it to crack. Suflicient strucv tural strength isproduced only by having the mold wall thicker than is necessary toproperly absorb the heat. from the solidifying lngot.

I have discovered that ingot molds made of cupola iron with the sulphurunder .05% are highly resistant to cracking even when they have arelatively large sectional area. The low sulphur cupola iron ingot moldstherefore fail only by the normal process of growth and tire cracking.

In the preferable practice of my invention I employ a cupola in whichthe metal charges are melted. A suitable de-sulphurizer such as soda ashis added to the molten metal 1n suflicient quantity to reduce thesulphur content below 05%. The de-sul hurized molten metal is thenpoured into t e ingot mold in the usual manner.

I claim:

An ingot mold made of cupola cast iron which contains sulphur under .05%and has high resistance to cracking through sudden expansion.

In testimony whereof, I hereunto afiix my signature. Y EDWARD R.WILLIAMS.

